loud hooting, screaming noise all the time, idle or fast

2005 FORD EXPEDITION
150,000 MILES • 5.4L • V8 • 2WD • AUTOMATIC
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KAYMACKSIMMONS
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  • 2 POSTS
this noise is all the time loud and has a wierd smell
Mar 30, 2015 at 7:43 AM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Check the accessory belt under the hood. It sounds loose. Chances are the tensioner is bad.
Mar 30, 2015 at 9:03 AM
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KAYMACKSIMMONS
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  • 2 POSTS
Changed belt that made no difference. sounds like it is coming from the back of the engine. I was told by a diesel mechanic that it was the hooter valve. What is that?
Mar 30, 2015 at 9:47 AM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
I hate to say it, but yes, it is an actual part. It is the crankcase vent valve. See the pic attached.
Image (Click to enlarge)
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Mar 30, 2015 at 7:36 PM